On this site you will find
iPhone/iPad/iPod touch Apps
Download pages for the AltairZ80 simulator which works on Windows, Macintosh, Linux and Zaurus. Also there is rich collection of operating systems including CP/M, programming languages such as Basic, C, Pascal, and application programs (e.g. WordStar and MultiPlan) ready to run on the simulator.
Download the XYZ GeoBench for Macintosh including Object Pascal source code. The GeoBench is an interactive system featuring algorithm animation for geometric computation.
You can find pictures and information about our travels on Verena's blog.
Proof of Peter Schorn: Assume there exist only m prime numbers.
Let n = m + 1. For two numbers i and j with 1 ≤ i < j ≤ n, then
Indeed, j = i + d, with 1 ≤ d < n, so
Therefore the n integers (n!)i + 1 (for i = 1, 2, …, n) are pairwise relatively prime. If pi is a prime dividing (n!)i + 1, then p1, p2, …, pn are distinct primes with n = m + 1, which is a contradiction [Paulo Ribenboim, The New Book of Prime Number Records, p. 5, Springer-Verlag 1996, 3rd edition].